Feb. 17, iq?.{ 
Parasitic Fungi Internal of Seed Corn 
505 
The kernel-rotted seeds (PI. 12, E) show extensive ramification of the 
fungus. All parts of the kernels are invaded by the mycelium, which 
is intercellular as well as intracellular. The resultant effect is similar 
to the rot produced by Gibberella saubinetii on corn and wheat. 
On culture media this fungus makes a slight to dense effused growth. 
With some strains there is a conspicuous pigmentation of the vegetative 
growth. The dense growth of mycelium often appears lavender in 
color, although this was not observed to be consistent for any one strain 
regardless of the medium. The catenulate conidia can easily be deter¬ 
mined by examining the aerial growth with the low-power objective. 
The chains of spores vary in number, and the maximum counted was 30 
spores in a single chain. It is not uncommon to find the conidia aggre¬ 
gated into heads, as shown in Plate 2, G-H. The conidiophores are 
simple or branched as shown in Plate 2, D-F. Strands of mycelium with 
numerous conidiophores often become interlaced. The conidia in chains 
are slightly pyriform, and the attenuated end of the spore is often sharply 
muticate. At time of germination they are considerably larger and often 
with one or two cross septa (PI. 2, B). The following measurements of 
microconidia by various investigators are given for comparison: 
Saccardo (27), host material.8 to 10/x by 2.5 to 3/1. 
Sheldon (29) ..6 to 10/x length. 
Tiraboschi (35).5 to 7*4 by 2 to 3.5*1. 
Hartley, Merrill, and Rhoads (15) .Prune agar 4.8 to 6.3*1 by 2.2 
to 3.1*1; corn meal 7.4 to 
11.1 A* length. 
Authors, host material...7 to 9*1 by 2.6 to 3. 5/i. 
Authors, dextrose medium.6.7 to 12*1 by 2.5 to 3.5**. 
The macroconidia are sparingly developed and were first observed in 
cultures that were at least 2 months old. Some strains even as old as 
that failed to develop macroconidia. We did not observe any of the 
macroconidia on host material. Marcoconidia in our cultures were 3- 
septate and measured 19 to 31.5 /x by 2.5 to 3.5 /x. Cultures on rice agar 
were first found to produce macroconidia, and similar results were ob¬ 
tained with cultures on steamed corn meal. 
DIPLODIA ZEAE (SCHW.) LEV. 
The term “dry rot” is often used in describing the effects on the ears 
produced by this fungus. However, the term seems no more applicable 
in this case than for the kernel-rot produced by Fusarium moniliforme 
and Gibberella saubinetii . 
In extreme infection of the ears the matting and rotting are similar 
to that described for Gibberella saubinetii (PI. 13) and which by growers 
is called moldy ears. The mycelium is established in a like manner, 
but no pink coloration is produced, such as is often found with infection 
of G. saubinetii. Kernels of both white and yellow varieties of corn 
show considerable blackening, which varies from irregular streaks to 
large areas involving more or less the entire kernel. In some instances 
the development of pycnidia is so abundant as to produce this blackened 
appearance. It is not uncommon to find scattered infected kernels at 
the tip of ears of which the upper part is brown to black in color. The 
pericarp in this region is of a fragile texture, and inside is found a powdery 
brown mass consisting of corroded starch grains with abundant brown 
septate mycelium. 
